1. Field of the Invention
The present invention relates to snow blower vehicles having a propulsion engine and a separate snow blower engine and methods of coordinating the operation of the two engines for improved snow blower performance.
2. Background Art
Snow blower vehicles are large, specialized trucks that are used to remove snow from roads and parking lots. Such vehicles are primarily used in areas where heavy snow accumulations cannot be effectively plowed. Snow blower vehicles may have a diesel propulsion engine and a separate diesel engine for driving a hydraulic pump that is used to turn the auger of the snow blower mechanism. When the snow blower vehicle is operating on heavy snow accumulations, the snow blower can become packed with snow and the snow blower engine can be overloaded if the vehicle speed that is controlled by the propulsion engine exceeds the rate at which snow can be cleared by the snow blower.
Performance of the snow blower can be adversely affected if the snow blower auger becomes jammed with snow. If the auger becomes jammed, it may be necessary to clear the auger manually or at least stop the vehicle until the snow blower can clear the snow-blowing mechanism. Repeatedly overloading the snow blower engine can result in damage to the engine.
The above problems and disadvantages are addressed by the present invention as summarized below.
According to the present invention, a method and apparatus is provided for improving the performance of a snow blower vehicle by adjusting the performance of the vehicle""s propulsion engine in response to an indication that the snow blower engine is overloaded.
According to one aspect of the invention, a snow blower vehicle is provided that includes a truck body on which a propulsion engine is secured for moving the snow blower vehicle. The propulsion engine includes an engine controller that controls the operation of the propulsion engine. A snow-blowing mechanism is also provided on the truck body. A blower engine is operatively connected to the snow-blowing mechanism. A first status signal is transmitted to the propulsion engine controller when the blower engine is being overloaded. A second status signal is transmitted to the propulsion engine controller when the blower engine is no longer being overloaded. When the propulsion engine controller receives the first status signal, the propulsion engine controller limits an output of the propulsion engine, such as speed or torque, until the second status signal is received or the propulsion engine is otherwise shut off. As such, coordinated operation takes place between the two separate engines for improved performance.
According to other aspects of the invention, the speed of the propulsion engine may be adjusted by the propulsion engine controller that may adjust a fueling rate parameter. The propulsion engine controller may also override an operator throttle control signal causing the vehicle to coast until a second status signal is received by the propulsion engine controller.
According to yet another aspect of the invention, a snow blower vehicle is provided that comprises a truck body from which a propulsion engine is provided for moving the snow blower vehicle. The propulsion engine has an engine controller that controls operation of the propulsion engine. A snow blowing mechanism is also provided on the truck body. A blower engine on the truck body is operatively connected to the snow blowing mechanism. A first status signal is transmitted to indicate that the blower engine is being overloaded. A second status signal is transmitted to indicate that the blower engine is not overloaded. When the first status signal is transmitted, a temporary limitation is imposed on the output of the propulsion engine. On the second output signal being transmitted after the temporary limitation is imposed on the output of the propulsion engine, the temporary limitation is then overridden.
According to other aspects of the invention, the first status signal may be used to generate an operator perceptible warning for instructing the operator to slow the speed of the snow blower vehicle until the second signal is transmitted. Alternatively, the first status signal may cause the operator throttle control to be disabled thereby causing the vehicle to coast until the second signal is transmitted.
According to another aspect of the method of the present invention, as applied to a snow blower vehicle having a propulsion engine and a snow blower engine where each engine has a controller, the method may be characterized as beginning with the step of determining that the snow blower engine is overloaded and generating a first signal. The first signal is then transmitted to the propulsion engine. In response, the operative propulsion engine is limited. It is next determined when the snow blower engine is no longer overloaded after the limiting strategy is implemented. A second signal is then transmitted to the propulsion engine reversing the step of limiting the propulsion engine. According to other aspects of the invention, the output limitation may be repeated to incrementally limit the output of the propulsion engine. Likewise, the second signal may be repeated to allow for incremental reduction of the limitation of the output of the propulsion engine.